Piperazine-2,5-dione derivatives and an α-pyrone polyketide from Penicillium griseofulvum and their immunosuppression activity

The potential of marine-derived piperazine alkaloids: Sources, structures and bioactivities

Marine-derived piperazine alkaloids (MDPAs) constitute a significant group of natural compounds known for their diverse structures and biological activities. Over the past five decades, substantial efforts have been devoted to isolating these alkaloids from marine sources and characterizing their chemical and bioactive profiles. To date, a total of 922 marine-derived piperazine alkaloids have been reported from various marine organisms. These compounds demonstrate a wide range of pharmacological properties, including cytotoxicity, antibacterial, antifungal, antiviral, and various other activities. Notably, among these activities, cytotoxicity emerges as the most prominent characteristic of marine-derived piperazine alkaloids. This review also summarizes the structure-activity relationship (SAR) studies associated with the cytotoxicity of these compounds. In summary, our objective is to provide an overview of the research progress concerning marine-derived piperazine alkaloids, with the aim of fostering their continued development and utilization.

Penisimplicins A and B: Novel Polyketide-Peptide Hybrid Alkaloids from the Fungus Penicillium simplicissimum JXCC5

In this study, two previously undescribed nitrogen-containing compounds, penisimplicins A (1) and B (2), were isolated from Penicillium simplicissimum JXCC5. The structures of 1 and 2 were elucidated on the basis of comprehensive spectroscopic data analysis, including 1D and 2D NMR and HRESIMS data. The absolute configuration of 2 was determined by Marfey's method, ECD calculation, and DP4+ analysis. Both structures of 1 and 2 feature an unprecedented manner of amino acid-derivatives attaching to a polyketide moiety by C-C bond. The postulated biosynthetic pathways for 1 and 2 were discussed. Additionally, compound 1 exhibited significant acetylcholinesterase inhibitory activity, with IC50 values of 6.35 μM.

7-Methoxy-13-dehydroxypaxilline: New indole diterpenoid from an endophytic fungus Penicillium sp. Nb 19

ABSTACTA chemical investigation of the endophyte Penicillium sp. Nb 19, isolated from leaves of the traditionally medical plant Baphicacanthus cusia (Nees) Bremek., yielded one new indole diterpenoid, 7-methoxy-13-dehydroxypaxilline (1) together with seven known metabolites (2-8). The obtained structure of compound 1 was elucidated by its spectroscopic data. In addition, the absolute configuration of compound 6 was confirmed by ECD for the first time. Compounds 1-6 were evaluated for antitumor activity against MCF-7, HepG2, and HCCC-9810 cell lines.

Pegriseofamines A-E: Five cyclopiazonic acid related indole alkaloids from the fungus Penicillium griseofulvum

Five new cyclopiazonic acid related indole alkaloids, pegriseofamines A-E (1-5), were isolated from the fungus Penicillium griseofulvum. Their structures and absolute configurations were determined by NMR, HRESIMS, quantum-chemical calculation, and X-ray diffraction experiments. Among them, pegriseofamine A (1) possesses an undescribed 6/5/6/7 tetracyclic ring system generated by the fusion of an azepine and an indole unit via a cyclohexane, and the postulated biosynthetic origin of 1 was discussed. Compound 4 could relieve liver injury and prevent hepatocyte apoptosis in ConA-induced autoimmune liver disease.

Two pairs of undescribed enantiomers isolated from the fungus Penicillium griseofulvum

Two pairs of undescribed enantiomers including a 2,5-diketopiperazine namely (±)-janthinolide G and a related analogue (±)-janthinolide H, were isolated from the crude extract of the fungus Penicillium griseofulvum together with five known compounds. Both two structures were determined by spectroscopic method and HRESIMS, whereas absolute stereochemistry was elucidated by using theoretical NMR calculation and ECD calculation. Janthinolide G is the first example of 2,5-diketopiperazine enantiomers with a cleavage diketopiperazine ring and comprises a terminal oxime group rarely seen in natural products. Biological screening of selected compounds found that 4 and 7 both exhibited weak α-glucosidase inhibitory effects, and a potential correlation was afforded by docking studies of α-glucosidase protein (PDB: 3TOP) and bioactive molecules. The plausible biosynthetic pathways of two unreported isolates are proposed here.